So, um, does anyone remember where we put that supermassive black hole?

You'd think a black hole with the mass of a decent-sized galaxy would be easy to find. But then, you're not looking for the one in the center of a galaxy in Abell 2261.

Abell 2261 is a ridiculously huge cluster of galaxies about 2.7 billion light years away from us. It has thousands of galaxies in it, and astronomers measure its total stellar content to equal the mass of a quadrillion (1015) Suns.

So yeah, it's a beefy cluster.

Like most big clusters, it has a big galaxy sitting in its center...